So...I'm going to ride my bike to work to save on fuel but use hydrogen "gas" to power my light?

Alright, alright, that's not fair, a lot of people just bike for fun - to be honest, environmental side effects are just a plus for me, not my real motivation to ride.

But even so, I don't really want one. Electricity comes to my home via wires and I don't have to do anything - I just plug in the battery and recharge it. That's it - I don't have to go to the store, don't have to order something online, etc etc. Heck, I always eat fresh fruits/vegetables at the cafeteria because then I don't have to go to the store before going home, and I don't have to throw food out every week because I didn't get around to eating the lettuce or something.

And a fuel cell powered light would be exactly the same - you always end up needing to order more, and since you can't recharge it you always have to carry a spare and stop and change them when they run out. Or - you end up throwing out a lot of half-used ones so you don't have to change the cell in the middle of a ride.

I don't know if we'll see them on bike stuff - we might with weight-weenie racing and such eventually (at the moment that thing only provides a usb amount of power - not a lot I don't think). But I think it would be more annoying than my current battery lights. I don't relish the idea of constantly spending money on new cartridges either - it's pretty impossible to believe they'll be anywhere near as cheap as electricity.

Interesting, but if you read a bit further you discover that the 12 Whrs of power that one filled cartridge supplies is equal to around 4 AA NiMH batteries fully charged. (the 1000 AA battery reference in the article refers to the total life of the cartidge including all refills, sort of like the fact that a rechargeable NiMH battery is good for 1000 charge cycles) You would then need to recharge your cartridge or slap in a charged one. For now, it's just a lot cheaper and easier to use rechargeable NiMH batteries -- at about $2 each they are kinda hard to beat.